System and method for a portable eye examination camera

ABSTRACT

A system and method for a portable eye examination camera is described herein. The system and method may include: a light source disposed within said portable camera at a set distance away from an eye of a patient; a first lens within said portable camera for focusing the light from said light source onto a retina of the eye and providing a wide field retinal image; a second lens for receiving said retinal image and causing a magnification of said retinal image; and a digital camera within a mobile computing device for recording said retinal image.

CROSS-REFERENCE

The present application is a continuation of U.S. application Ser. No.16/152,294, filed on Oct. 4, 2018, which is a continuation of U.S.application Ser. No. 15/076,824, filed on Mar. 22, 2016, now issued U.S.Pat. No. 10,105,051, which claims benefit of U.S. ProvisionalApplication Ser. No. 62/136,609, entitled “PORTABLE INDIRECTOPHTHALMOSCOPY BASED FUNDUS CAMERA for ROP SCREENING”, filed on Mar. 22,2015, which are hereby incorporated by reference in their entirety.

DESCRIPTION WITH REFERENCE TO DRAWINGS

For a more complete understanding of the present invention, includingits features and advantages, reference is now made to the detaileddescription of the invention taken in conjunction with the accompanyingdrawing in which:

FIG. 1 shows the various components of the present invention; and

FIG. 2 shows another illustrations of the optical system of the presentinvention.

DETAILED DESCRIPTION

While the making and using of various embodiments of the presentinvention are discussed in detail below, it should be appreciated thatthe present invention provides many applicable inventive concepts thatmay be embodied in a wide variety of specific contexts. The specificembodiments discussed herein are merely illustrative of specific ways tomake and use the invention and do not delimit the scope of theinvention.

There are many diseases that affect the retina. Normally, an examinationof the retina is effected by an ophthalmoscope. The basic requirement ofan ophthalmoscope, whether it be direct or indirect, is to illuminatethe retina, which can then be focused onto the eye of an examiningdoctor. The focusing of the illuminated retina is effected by a systemof lenses provided in the ophthalmoscope. An ophthalmoscope may be adirect or indirect. With a direct ophthalmoscope, the images are erect,magnified and virtual. In Indirect ophthalmoscope, the images formed areinverted, small or less magnified and real. A disadvantage associatedwith direct ophthalmoscope is that it does not have a wide field.

Fundus or retinal cameras which get a wide field of view, presentlyknown in the art have a circular source of light besides the lenssystem. A disadvantage associated with such a camera is that the sourceof light touches the periphery of the cornea. In another known camera,the source of light comprises an Ultra Violet source, which touches theglobe of the eye. Both of such known cameras are contact cameras havingthe distinct advantage of a wide field of view of the retina. However, adisadvantage associated with such known cameras is that of the contactbetween the eye and the light source. Such a contact could result intransmission of infection and chances of causing injury to the eye. Yetanother disadvantage is that the magnification is small.

In order to obviate the aforesaid disadvantage, it is known to provide adirect ophthalmoscope fundus or retinal camera. In such a known camera,and in order to improve the quality of the images and to avoid reflexes,the optical system incorporated in the camera is complex and bulky. Suchcameras are heavy equipment and cannot be easily moved afterinstallation, hence cannot be used for field work. Further suchnon-contact fundus cameras have a field of view ranging from 15° to 60°.This is inadequate for photographing the periphery of retina, which isessential for recording the changes of retinopathy of prematurity.

Another method currently used in the field includes a retinal camerahaving an illumination source and an optical system for projecting thelight onto a retina under examination. The camera further includes afilter means disposed substantially conjugate to the retina of the eyeso as to illuminate the eye. The filter means includes at least onefilter member with a disc shaped transmitting base plates, a first andsecond circular semi-transmitting surface. However, this system's acamera has a complicated illumination optical means.

In contrast, the present invention improves several aspects of thecurrent systems and method used in field. One embodiment of the presentinvention relates to a retinal or fundus camera. Specifically, theretinal or fundus camera of the present embodiment is adapted to providea photo documentation of the retina of the eye.

One aspect of this invention includes a retinal or fundus camera that isportable.

Another aspect of this invention includes a retinal or fundus camera,which has a wide field.

Another aspect of this invention includes a retinal or fundus camera,which does not contact the eye.

Another aspect of the invention includes a retinal camera, which cantake pictures of retina in un-dilated pupil (4 to 5 mm size).

Another aspect of this invention includes a retinal or fundus camera,which has a simple optical system.

Another aspect of this invention includes a retinal or fundus camera,which is efficient.

One embodiment of the present invention includes a retinal or funduscamera which includes: a light source (e.g. Light Emitting Diode (LED))within the camera and placed close to the camera lens and away from theeye of a patient to illuminate the retina of the patient's eye. Theembodiment also includes: an Infra-Red LED within the camera and placedclose to the camera lens and away from the eye of a patient toilluminate the retina of the patient's eye, without initiating the lightreflex—thus keeping the pupil dilated for photographing the retina whena white LED flashes. In addition, the embodiment also includes: a 60 to90 Diopter lens for receiving the reflection light from the retina andforming a real and magnified image of the retina. Moreover, theembodiment also includes: a 20 Diopter lens in front of the camera lensto provide further magnification of the retinal image. The embodimentfurther includes a portable computing device for recording the image.

In accordance with this invention, the first lens could have a highpower of (e.g. such as 60 to 90) diopters—the greater the power of thelens translates to a larger the field of view. Further, such a lenscomprises a biconvex aspherical lens. In this embodiment, the secondlens has a power less than that of the first lens (e.g. such as 20 to 30diopters), so as to provide a greater magnification of the retinal imageand to act as a close up lens for the camera. Such a lens is usually abiconvex achromatic lens.

Thus, according to the present embodiment, the lens system has a varyingpower of (e.g. such as 20 to 90) Diopters. As the power of the lensincreases, the field becomes wider but with less magnification. Thus, inthis embodiment, the first lens has a higher power (e.g. such as 60 to90 D), so that the field of view increases. However, the power of thefirst lens in this embodiment is not higher than 90 diopters, as thelens would then be too close to the eyeball under examination.Conversely, a magnification of the image is achieved by the second lensin this embodiment. Accordingly, the distance between the first andsecond lens is the sum of the focal length of the first and second lens.

Now referring to FIGS. 1 and 2, Housing 100 includes of a re-tractablemetallic tubular extension 104 that holds a 60 Diopter Lens 122 and 20Diopter Lens 120 and a plastic casing 108. A light source 106, anInfra-Red light source 118 and Selector switch 114 and a power sourcebattery 110 is disposed within the plastic casing 108.

In addition, the embodiment also includes three polarizing filters 300.A first filter is placed in front of the white light LED 106 and asecond one is placed in front of 20 D magnifying lens 120. A thirdfilter is also placed in front of the IR LED light source 118 similarlyto the one placed in front of the white light LED source 106. Moreover,the second filter is placed at 90 degree polarity in respect to thefirst and third filters.

In addition, Housing 102, in this embodiment, is a digital cameracombined in a cell phone 116. Moreover, the fundus camera has an opticalsystem including of LED light source 106 and Infra-Red light source 118connected to the power source battery 110. Furthermore, the SelectorSwitch 114 allows switching between LED light source 106 and Infra-RedLED 118. The light from either light source 106, 118 is focused onto aretina 222 of a patient through lens 122. As described herein above,this lens 122 has a high power such as 60 to 90 diopters, so as toprovide a wide field of view for example, up to 110o. Further, lens 122receives the image of the retina 222 at its focal point F1, which isthen transmitted to a second lens 120 having a power less than that oflens 122. Thus, lens 120 acts as a magnifying lens and a close up lensfor the camera. Accordingly, the image is at the focal length of lens120, which is greater than the focal length of lens 122.

Moreover, the light from light source 106 or 118 is disposed such thatit is almost coaxial with the receiving optics.

The above embodiments show using an alternative light source other thanusing the light source (e.g. normal flash light used in most digitalcameras) within, or adjacent to, the cell phone. These unique aspectallows near alignment of projected light with the optical axis off thelenses. In addition, the present invention contemplates using any otherportable computing device as a controller for the optical system, andnot restricted to just a digital camera or cell phone. Further, althoughthis embodiment shows a somewhat singular tube, the present invention isnot restricted to a particular version of a tube and includes any typeof retracting metallic tube.

Although this invention has been described with reference to anillustrative embodiment, this description is not intended to limit thescope of the invention. Various modifications and combinations of theillustrative embodiments as well as other embodiments of the inventionwill be apparent to persons skilled in the art upon reference to thedescription. It is therefore intended that the appended claimsaccomplish any such modifications or embodiments.

1-21. (canceled)
 22. A method of providing a retinal image of a patientcomprising: illuminating a retina of the patient with an LED lightsource within a portable camera, wherein the portable camera has a firstlens and a second lens, and wherein the first lens is capable offocusing light from the LED light source onto the retina of the patientand providing a wide field retinal image, and wherein the second lens iscapable of receiving the retinal image and causing a magnification ofthe retinal image; illuminating the retina of the eye with the LED lightsource at a set distance away from the eye; and recording the retinalimage.
 23. The method of claim 22, wherein the first lens has a powergreater than said second lens.
 24. The method of claim 22, wherein theLED light source is substantially coaxial with that of receiving optics.25. The method of claim 22, wherein said first lens is a biconvexaspherical lens.
 26. The method of claim 22, wherein said second lens isa biconvex achromatic lens.
 27. The method of claim 22, wherein a focallength of said second lens is greater than that a focal length of saidfirst lens.
 28. The method of claim 22, wherein the distance betweensaid first and second lens is a sum of the focal lengths of said firstand second lens.
 29. The method of claim 22, wherein the portable camerafurther comprises two polarizing filters: a first filter placed in frontof the LED light source and a second filter placed in front of secondlens, wherein the second filter is placed at 90 degree polarity inrespect to the first filter.
 30. The method of claim 22, wherein themethod is performed without dilating a pupil of the eye.